Wave Optics Questions and Answers

3 In Young s double slit experiment separation between the slits is 0 5 mm Source of light S is placed at a distance of 0 5 mm from the slit S as shown in the figure To have central maxima at mid point O the glass plate of refractive index 1 5 is placed in front of S The thickness of the plate is S 0 5 mm S 15 and 0 5 mm 1 2 1 mm 3 2 mm S 2 2 1 mm 1 4 mm

xample 10 15 White coherent light 400 nm 700 nm is se hrough the slits of a YDSE d 0 5 mm D 50 cm There i a hole in the screen at a point 1 0 mm away along the width c the fringes from the central line i Which wavelength will be absent in the light coming from the hole ii Which wavelength s will have a strong intensity 0 5 mm 1 50 cm 1 0 mm

31 A ray of light is incident on the surface of a glass plate of refractive index 3 at the polarising angle The angle of refraction is 1 60 3 45 When n 2 30 4 50

M White light is incident on a soap film of refractive index 4 at an angle of refraction 30 The transmitted light 3 is observed to have a dark band for wavelength 6 x 10 5 cm Calculate the minimum thickness of the film 4 mub mimima nota ma

C n n D None of t From a medium of index of refraction n monochromatic light of wavelength is incident normally on a thin film of uniform thickness L where L 0 1 and index of refraction n The light transmitted by the film travels into a medium with refractive index n The value of minimum film thickness when maximum light is transmitted if n n n is A n 201 n B 402 C 402 D 202

In Young s double slit expt incoherent sources of equal amplitude a are used Intensity at the centre is found to be I The in coherent sources were then replaced by coherent sources of amp a The intensity at centre is found to be I The correct relation between I and I is 4 21 c 16 I 1 2 a

If the maximum and minimum intensity in the fringe pattern of YDSE are max and min then fringe visibility is given by Imax 1 Imin 2 Imax Imin 2

1 A monochromatic light source s of wavelength 440 nm is placed slightly above a plane mirror M as shown Image of s in M can be used as a virtual source to produce interference fringes on the screen The distance of sources from o is 20 0 cm and the distance of screen from o is 100 C cm figure is not to scale If the angle 0 50 x 10 radius the width of the interference fringes observed on the screen is a 2 20 mm b 2 64 mm c 1 10 mm d 0 55 MIT So 50 0 cm Screen

A bulb is located on a wall Its image is to be obtained on a parallel wall with the help of a convex lens If the distance between the two walls is d then required focal length will be 1 Only 2 Only d D N 3 More than d 4 but less than d 4 Less than or equal to 4 d 02

The star Betelgeuse has a surface temperature of 3000 K and is 600 times the diameter of our sun Diameter of sun is 7 x 10 km Assume that it radiates like an ideal blackbody If Betelgeuse were to radiate all of its energy at the peak intensity wavelength then number of photons radiated per second are x x 104 x will be 49

37 In Young s double slit experiment the separation between the slits is 42 is the wavelength of the light used The maximum number of maxima formed on the screen placed at a distance of 1 m from the slits is 1 6 3 9 2 7 4 11

10 In a double slit experiment the two slits are 1 mm apart and the screen is placed 1 m away A monochromatic light of wavelength 500 nm is used What will be the width of each slit for obtaining ten maxima of double slit within the central maxima of single slit pattern 1 0 1 mm 3 0 02 mm 2 0 5 mm 4 0 2 mm

8 35 our tion not 21 light 3 T I R of light An object is immersed in a fluid In order that the object becomes invisible it should 4 Diffraction of light 1 Bahave as a perfect reflector Absorb all light falling on it 3 Have refractive index one MENT 02 EXERCISE ASS FXERCISE P65 4 Have refractive index exactly matching with that of the surrounding fluid

5 Two coherenet sources are 0 18 mm apart and the fringes are abserved on a screen 80 cm away It is found that with a certain monochromatic source of light the fourth bright fringe is situated at a distacne of 10 8 mm from the central fringe The wavelength of light in A is

In single slit diffraction experiment if slit width is made double of original then intensity increases 1 Two times 2 Four times 3 Eight times 4 Sixteen times

20 In a single slit diffraction experiment first minimum for red light 660 nm coincides with first maxima of Then 1 3300 A 3 4400 A 2 6600 A 4 1100 A

In given arrangement there are two thin lens are arranged as shown in the figure The separation between them is 2f where fis focal length for each lens x coordinate of final image for a 30 is Nf Find the value of N 3 AY 2f 1 a 30 X

9 A slit 5 cm wide is irradiated normally with micro waves of wavelength 1 cm Then the angular spread of the central maximum on either side of the incident light is nearly 1 1 5 radian 2 4 radian

2004 The maximum number of possible interference maxima for slit separation equal to twice the wavelength in Young s double slit experiment is b five a infinite c three d zero n 2004

Which of following nature of light waves is supported by the phenomenon of interference 1 longitudinal 2 transverse 3 both transverse and longitudinal 4 None of the above ENG 02 WAVE OPTICS 02 EXERCISE P65

Th Pre Medical Physics In Young s double slit experiment one of the slits is so painted that intensity of light emitted from it is half of that of the light emitted from other slit Then Imet 152 1 fringe system will disappear 2 bright fringes will become brighter and dark fringes will be darker S 3 both bright and dark fringes will become darker 4 dark fringes will become less dark and bright fringes will become less bright K

The incident intensity on a horizontal surface at sea level from sun is about 2000 W m Assuming that half of this intensity is reflected and half is absorbed the radiation pressure on this horizontal surface is 1 1 10 5 Pa 2 1 5 10 Pa 3 2 87 x 10 5 Pa 4 3 3 x 10 5 Pa

If diffraction occurs through a single slit then intensity of first secondary maxima become of central maxima 3 75 Z 1 4 2 25 4 50

MP 30 MI YA Magnification of a compound microscope is 30 Focal length of eye piece is 5 cm and the image is form at least distance of distinct vision Find the magnification of objective V225 20 vo

9 In YDSE d 0 8 mm 7200 and D 2 m The minimum distance from central maximum a which the average intensity is 50 of the maximum is 1 0 45 mm 3 125 mm 2 0 75 mm 4 2 50 mm

1 In a Young s double slit experiment separation between the slits is 2 x 103 m and distance of the screen from the slit is 2 5 m Light in the range of 2000 8000 A is allowed to fall on the slits Wavelength in the visible region that will be present on the screen at 10 3 m from the central maxima will be A 4000 C 6000 B 5000 D 8000

A parall beam of light of intensity I is incident normally on a plane surface A which absorbs 50 of the incident light The reflected light falls on B which is perfect reflector the light reflected by B is again partly reflected and partly absorbed and this process continues For all absorption by A asborption coefficient is 0 5 The pressure experienced by A due to light is Faunp p 1 5 I A B A B H C 31 D 31 ma 75 fart 2

wo narrow slits are 0 27 mm apart The 5th order dark fringe is 0 9 from the central bright fringe What is the wavelength of the light

Plane wavefronts are incident on a as shown The reflected wavefronts will be D 1 3 4

In double slit experiment the angular width of the fringes is 0 20 for the sodium light 2 5890A In order to increase the angular width of the fringes by 10 the necessary change in the wavelength is 1 Increase of 589A 2 Decrease of 589 3 Increase of 6479A 57 Cod 10 4 Zero or 5890 Ans ota TT 12 maxima is obse covered then become 1 1 2 Calculate a 2 6000 1 28 4 Af diffract intensity 1 4

58 A boy is trying to start a fire by focusing Sunlight on a piece of paper using an equiconvex lens of focal length 10 cm The diameter of the Sun 1 39 109 m and its mean distance from the eart is 1 5 x 10 m What is the diameter of the Sum image on the paper AIPMT Prelims 200 1 12 4 x 10 m 2 9 2 x 10 m

The ionosphere bends the E M waves having the frequencies 1 less than 40 MHz 3 nothing is certain 2 beyond 40 MHz 4 depends on the moisture present

A narrow steel rod of length L is rigidly clamped at its mid point and transverse standing waves of frequenc f are set up in it by touching the prong of a tuning fork at a point L 3 from one free end The speed o transverse waves in the plate is c Then f can have values A 3c 2L B 5c 2L 7c C L 2L D 9c 2L wir

1 75 kg particle moves as a function of time as follows x 3 3cos 3 7t 1 3 where distance is measured in meters and time in seconds Find the velocity of this particle at t 1 26 s

A 6 3 m long string has a mass of 2 15g What is the mass in kg of an object hung from its end if a 195 Hz wave has a wavelength of 97 cm Round your answer to 3 decimal places

Question 1 of 10 What are two ways in which ultrasound technology produces images A By measuring the time it takes for reflected sound waves to be detected B By the absorption of sound waves in the body C By using sound in frequencies that reflect off body tissues By detecting the frequencies of emitted sound waves SUBMIT

Refraction is caused when parts of the wave fronts travel at different speeds Select one True O False

Who first separated white light into colors Isaac Newton Galileo Albert Einstein

5 An angle of incidence of 20 in water results in an angle of refraction of 15 a Is the second medium more of less optically dense than the first medium The Second one because it bands towards the normal b Find the n of the second medium 11 0 34 0 26 1 31 nw sini n V Medum Sinr

Question 21 Which of the following statements is true of the electromagnetic spectr O Our eyes can see visible light x rays ultraviolet and gamma rays O Visible light is an extremely small portion of the electromagnetic spectrum All electromagnetic waves need a medium through which to travel

Substances that absorb light are called pigments Different pigments show maximum absorption of light at different wavelengths reflecting the unabsorbed wavelengths Varying forms of chlorophyll in plants lead to a large variety in the coloring of plant leaves due to discrete absorption profiles Figure 1 shows the absorption spectra for chlorophyll a chlorophyll b and carotene important compounds in photosynthesis These spectra show the relative absorption of light by each compound as a function of wavelength 3 3 1 Determining Support Figure 2 shows how the rate of photosynthesis varies with the wavelength of absorbed light for chlorophyll a absorbance 300 violet blue green yellow orange red Key chlorophyll a chlorophyll b carotene 400 500 wavelength nm Figure 1 600 700 rate of photosynthesis 1 mL O min 6420 8642 16 14 12 10 0 400 450 500 550 600 650 700 750 wavelength nm Figure 2 Which of the following is best supported by Figure 1 estud A Chlorophyll a absorbs the most light at blue and red wavelengths B Chlorophyll a absorbs the most light at green and yellow wavelengths C Chlorophyll a absorbs the most light at violet and green wavelengths D Chlorophyll a absorbs the most light at yellow and orange wavelengths

White light falls normally on a transmission grating that contains N 9176 lines The grating has a width w 0 0113 m a 1 point Which formula can be used to calculate the separation distance d between successive slits on the grating refer to the formula sheet and select the number of the correct formula from the list b 5 points Calculate d d m c 5 points Assume d 8 18 107 m at what angle in degrees will red light A 6 11 107 m emerge in the first order spectrum do not consider the small angle approximation 0 d 3 points Calculate the wavelength of this red light A 6 11 10 7 m in a material where the index of refraction is 1 28

5 In each diagram In each diagram tell which way the missing ray will bend towards or away from the normal Medium 1 is more optically dense Medium 1 Medium 2 Medium 1 is less optically dense Medium 1 Medium 2 1 1 Light travels fastest in medium 1 Medium 1 Medium 2

10 Certain relationships should clearly show in all of your wavefront diagrams a How does the incident frequency compare to the refracted frequency How do you know b How does the incident wavelength compare to the refracted wavelength How do you know c How does the incident wavespeed compare to the refracted wavespeed How do you know

2 Collate d Name Table1 Image and Object Distances de m Distance from do m light source to screen m 0 36m Silk 0 50 o ile silla 13m I Il TANONIM SVEJO 16 honestinga bao digns Iso07 he 0 80 M 1to sulas 0 90 M 0 60 bozzon 0 465 m 0 135m 0 0215 tud oril ponts on Ingman DEWAR PRAELAT Table 2 Focal Length error do 0 115m 0 70 eu bomol agterdo vi brigen Result from x intercept 1 do m 0 11 m 0 49m 10 0909 0 0204 1 d m 0 14m 0 0278 0 0714 0 37m 0 0769 0 0270 0 055m 0 147m 0 0741 bas como nigil alanl silt browol toto wak ansiti neowind more 2014 olitus tiedottabile S 0 125m0 01740 0800b Une constails ogamas onli 0 575m 0 11 m 0 69m 0 09090 0145 i 01 min sa W 10 250 m 06 0 EU con reside que o E 0 68 m 0 12 m 0 01470 0833 alignal inst bon puny all to19 1 0 11 m 0 79m 0 0909 0 0127 bidh mbio bim 0 78m 0 12m 0 0128 0 0833nley und tarybart waimavano noviy not dianal Result from y intercept difference between results from intercepts Average of results from intercepts 0 585 m 0 0870 0 0171 1911 TO DEL TR Image size m Object size m 109HT 235 0 017m0 147 m F m 11 2160 01 Pasaib toside hita ogni situ mc110 no misn emblodt no simbssor mi 1 C

02010 Pearson Education inc A light shines through a fish tank What is the angle of refraction if the incident ray from the glass is 45 Sin 02 1 sin 45 1 5 0 4714 D2 sin 1 0 4714 02 28 125 a h What if the light was shown at 30 What if the light was shown at 60 2

0 2015 Pan Edication inc n sin 0 n sin 0 Snell s law for refraction between two media 18 2 A light shines through a fish tank What is the angle of refraction if the incident ray from the glass is 45

11 What is the minimum thickness of an oil film on a surface of water which will appear black if illuminated from air with light of 5 0x10 4 Hz frequency noil 1 65 nwater 1 33 a 152 nm b 130 nm c 211 nm d 182 nm Ie 167 nm

In a standard Young s double slit experiment a thin layer of air of thickness t2 is enclosed in a hollow squarish transparent container of wall thickness t as shown in figure a 0 1 t t When it is placed in front of one slit causes the shifting of central maxima by 4 fringe width and when the entire setup is immersed in a liquid then it is observed that the central maxima is restored to the original position Find the side length of container in m

A loudspeaker is producing a single frequency of sound waves a pure tone at 198 Hz If a second loudspeaker is placed nearby and it produces sound waves at 202 Hz with a similar loudness what will be the frequency of the beats that people will hear in hertz Hz There is no penalty for including too many significant figures but rounding to too few sig figs may cause Laulima to judge your answer to be wrong Do NOT enter units with your answer enter only a numerical response Laulima will count non numerical answers as incorrect Partial credit is NOT possible